1. Field of the Invention
The present invention relates to a video reproducing system, and more particularly, to a memory management apparatus and method for preventing image tearing in the video reproducing system.
2. Description of the Related Art
FIG. 1 is a schematic block diagram partially showing a conventional video reproducing system. Generally, a video reproducing system includes a scaler 100 and a memory 110 as shown in FIG. 1. In FIG. 1, the scaler 100 compresses or expands input image data to fit the resolution of a display (not shown) on which the image data are to be displayed. In addition, the scaler 100 can also perform frame-rate conversion as well as generating vertical and horizontal frequencies required for displaying.
The memory 110 stores data associated with the scaler 100. In other words, the scaler 100 converts the format of the input image data into an image format that corresponds to the resolution of the display, and then writes the format-converted input image data into the memory 110. The scaler 100 may also read format-converted input image data stored in the memory 110 and output it to the display. During the read/write operations of the memory 110, the data output rate may often exceed the data input rate. When this occurs, the data being output from the memory 110 may not be new data which has not yet been read from the memory 110, but instead it may be old data which has already been read out from the memory 110, thereby causing image tearing to occur on the display. Image tearing typically occurs when the screen refresh rate, which corresponds to the data input rate of the memory 110, is out of sync with the frame rate of the display, which corresponds to the data output rate of the memory 110. In image tearing, the top of frame data simultaneously appears with the bottom of other frame data in a single picture. When this occurs, a gap between the two partial images may be observed.